Vibrator converter with resistors



Oct. 30, 1951 C. HUETTEN VIBRATOR CONVERTER WITH RESISTORS Fi1`ed lay 2. 1947 Z9 uncommon m55/5 r/ VE .5P/STER w IN1/Emol@ (/arem'@ Hai/few BY/f@ M Patented Oct. 30, 1951 2,573,262 VIBRATOR CONVERTER WITH BESISTORS Clarence Hnetten, Indianapolis, Ind., assigner to P. B. Mallory Co., Inc., Indianapolis, Ind., a

corporation of Delaware Application May 2, 1947, Serial No. 745,623

2 Claims. (Cl. 321-49) This invention relates to vibratory interrupter systems and to circuits therefor.

It is an object of the invention to provide an improved circuit for use in vibrator systems and to improve the operation of such systems.

Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the appended claims.

The invention accordingly comprises the features of construction, combination of elements, arrangement of parts, and methods of manufacture referred to above or which will be brought out and exemplified in the disclosure hereinafter set forth, including the illustrations in the drawings, the scope of the invention being indicated in the appended claims.

in the drawing:

Figure l is a schematic circuit diagram showing the novel vibrator circuit; and

Figure 2 is a view of a vibrator constructed in accordance with the invention.

Heretofore, considerable difliculty has been experienced in the operation of vibrator systems, particularly with vibrators having a driver contact, in that arcing occurs each time the driver contact is opened. It has been proposed to minimize or eliminate this difficulty by connecting a resistor between the driver contact and the reed. Although sparking didculties may be somewhat minimized in this manner, disadvantages are inherent in this system due to the fact that current iiows continuously through the driver coil, thus reducing the efficiency of the system in two ways. First, there is a larger drain on the current supply or battery and, second, the efiiciency of the driver coil is reduced as a result of decreased fiux modulation thereof. This decreased flux modulation results from the fact that continuous passage of current through the driver coil prevents the complete collapse of the driver coil magnetic field after each cycle of energization thereof which is necessary for efficient operation.

In a circuit where the resistor is connected across the driver contacts, the current, and hence the magnetomotive force, after contacts break will decay approximately as i in Lf i=e L where 'it is the coil current at time of break, R is the total resistance of the driver coil and the suppression resistor, t equals the off contact time, L equals the driver coil inductance, and where the symbole equals the induced voltage. Where t is small, as in a high frequency vibrator, the driver coil current, and therefore the flux, does not drop to zero before the contacts close to start the next succeeding cycle of operation. Accordingly, at all times, a substantial current flows through the driver coil and there is a substantial flux density in the driver coil magnetic circuit,

preventing efficient flux modulation and decreasing the eiliciency of the system.

In accordance with the invention, these diiilculties are eliminated or substantially overcome by connecting the resistor between the driver contact and the inertia side interrupter contact instead of across the driver contacts. In this position, the resistor is effective not only to provide arc suppression but also to improve the ux modulation of the driver coil and thereby increase the efficiency thereof. This results from the fact that, during each cycle, after the driver contacts are opened to deenergize the driver coil, a current is induced in the idle half of the transformer winding which sends a pulse of current through the driver coil of opposite polarity with respect to the current normally passing therethrough. Accordingly, the magnetic field of the driver coil is rapidly collapsed in the period following each energization causing a greater variation in the iiux density of the field during each cycle which results in increased efficiency of operation.

The invention further contemplates the provision of a resistive spacing member mounted in the stack for obtaining the desirable results of connecting a resistance between the driver contact and the inertia side interrupter contact. In this manner, the resistance is introduced without adding extra size or weight to the vibrator assembly and without the necessity of providing additional circuit connections.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In the following description and in the claims, parts will be identied by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring now to Figure l which is a circuit diagram of a vibrator power supply unit embodying the principles of the invention, the reed` mounted at one side of the reed while a normally closed driver contact I5 and an inertia. side interrupter contact I6 are mounted at the other side of the reed. As shown, the contacts I4, I5 and I6 cooperate with suitable contact pieces mounted on the reed. It will be apparent that the reed is adapted to vibrate and alternately engage the interrupter contacts I4 and I6.

The vibrator system further comprises a transformer primary 20 which is divided into a pole side primary winding 2| and an inertia side primary winding 22 by a center tap 23. A battery 24 or other suitable current source is connected between the reed I and the center tap 23 while the ends of the transformer primary are connected, respectively, to the interrupter contacts I4 and I6 as by conductors 25, 26. Accordingly, it will be apparent that the primary windings 2I, 22 are alternately energized as the reed vibrates and engages the interrupter contacts I4 and I6.

The terminal of the battery adjacent the center tap 23 is connected by a conductor 21 to the driver coil I2 which, in turn, is connected to the driver contact I5. Consequently, when the contact I is closed, the driver coil is energized thus attracting the armature Il and moving the reed into engagement with the pole side interrupter contact I4. Thereupon, the driver contact I5 opens and the coil is deenergized whereby the reed is urged toward the inertia side interrupter contact I6 by the resiliency of the material from which said reed is formed. As the reed engages the driver contact I5, the coil is again energized and a new cycle of operation is initiated. The resultant vibration of the reed supplies pulses of electrical energy to the primary winding which are stepped up by the transformer and appear as4 an alternating current across the output terminals 28 which are connected to the secondary winding 29 of the transformer.

In accordance with the invention, a resistor 33 is connected between the driver contact I5 and the inertia side interrupter contact I6. It will be understood that the value of this resistor is suitably chosen so that the inductive energy is discharged through the primary winding rather than producing a spark between the driver contact and the reed. I have found a suitable value for this resistor to be about 150 ohms when used with a conventional vibrator and a 6 volt'battery. The resistor 30 also functions to increase the flux modulation of the driver coil magnetic circuit, thereby improving the efficiency of the driver coil magnetic system. As will be understood by those skilled in the art, when the contact I5 is closed, the coll I2 is energized by current of such polarity as to establish a magnetic neld in the coil and pole piece I3 which attracts the armature II and opens the contact I5. A short interval after the driver contact I5 is opened, the pole side interrupter contacts I4 close. thereby connecting the battery in the circuit with the winding 2I. When the winding 2| is energized in this manner, a voltage is induced in winding 22 in such polarity as to oppose the current through the driver coil by a circuit which includes winding 22, conductor 21, driver coil I2, resistor 30 and conductor 26. This opposing voltage causes the current in coil I2 to rapidly become approximately zero. As a result, connection. of the resistor 30 as described effects maximum variation in the iiux density of the magnetic eld and increased eiliciency of the driver coil circuit. The resistor 36 is also useful in discharging the inductive energy of the driver coil into the transformer thereby to improve the overall emciency of the system. Thus, immediately after the driver contact break, the self-induced voltage of the driver coil may be higher than the opposing voltage of winding 22 and this will produce a current in a direction which aids winding 2I in supplying magnetizing current.

However, the self-induced voltage of the vibrator coil decays exponentially and thereby allows the previously mentioned opposing voltage of the winding 22 to be effective in deenergizing coil I2. The advantages of the described circuit may be conveniently obtained by the use of the vibrator structure shownin Figure 2. This vibrator comprises a hook shaped frame portion 35 having a pole piece 36 brazed or otherwise suitably secured to the hooked portion thereof. Mounted on the pole piece 36 is a driver coil 31 which has one terminal thereof connected to the frame, the other terminal having attached thereto a lead 38 which is adapted for connec- A plurality of contact springs are disposed between the aforementioned spacers, said springs carrying, respectively, a pole side interrupter contact 46, a pole side rectifier contact 45, an inertia side rectifier contact 44, and an inertia side interrupter contact 43. Also mounted in the stack 39 is a exible reed 41 having, at the free end thereof, an armature 49 which is adapted to be attracted by the pole piece 36. The reed also has a number of arms 49 secured thereto which are adapted, respectively, for engagement with the contacts 43 to 46. Also secured to the reed 41 is a driver contact 50 which cooperates with a fixed contact 5I electrically and mechanically connected to the frame by a spring arm 52.

It Vwill be apparent that the reed, driver coil, driver contact and the interrupter contacts are adapted to be connected in circuit in the manner shown in Figure 1 to cause periodic vibration of the reed and alternate closure of the interrupter contacts. When the vibrator is so connected the rectifier contacts are adapted to be connected in the circuit in a well understood manner to rectify the alternating current appearing across the secondary winding of the transformer 20. It will be noted that the resistive spacer 4I is connected between the inertia side interrupter contact 43 and the driver contact 5I, the latter connection being made through the frame 35. This spacer may be conveniently constructed of such thickness as to give a resistance of about 150 ohms. The use of the resistive spacer 4I enables the advantages of the circuit of Figure 1 to be obtained, in that sparking at the contacts is substantially eliminated and the flux modulation of the driver coil is increased with resultant higher efficiency; however, no extra weight or bulk is added to the assembly, nor is it necessary to provide the resistor 30 as a separate part with resultant increased cost and complexity of wiring.

While the present invention, as to its objects A and advantages, has been described herein as the spirit and scope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a vibratory interrupter system, a vibrator comprising a reed, a pole side interrupter contact and a driver coil assembly including a pole piece mounted at one side of the reed, a driver contact and an inertia side interrupter contact mounted at the other side of said reed, a transformer having a tapped primary winding connected between said interrupter contacts, a source of direct current connected between said reed and the tap on said winding, a circuit for periodically energizing said driver coil including the current source, the reed, and the driver contact, and a circuit including a resistor connected between said driver contact and said inertia side interrupter contact for preventing contact arcing and promoting eiciency of operation of the driver coil.

2. In a vibratory interrupter system, a vibrator comprising a, frame; a reed a driver coil `having two ends, a pole piece therefor, and a pole side interrupter contact mounted at one side of the reed; a. driver contact connected to one end of said coil and an inertia side interrupter contact mounted at the other side of said reed, said driver contact being eletrically connected to said frame; spring arms carrying said interrupter contacts; a stack comprising a plurality of insulative spacers interposed between said reed and said spring arms, and a spacer of resistance material between the frame and the arm carrying said inertia side interrupter contact; a transformer having a tapped primary winding di- 6 vided into pole side and inertia side sections which are connected, respectively. to said interrupter contacts; and a source of direct current connected between said reed and the tap on said Winding, said tap being connected to said other side of said coil.

CLARENCE HUE'I'I'EN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 320,585 Pfannkuche June 23, 1885 1,924,082 Barrett Aug. 22, 1333 2,078,316 Dressel Apr. 27, 1937 2,096,962 Dressel Oct. 26, 1937 2,120,273 Barrett June 14, 1938 2,156,708 Sullivan Mar. 2, 1939 2,176,447 Vilkomerson Oct. 17, 1939 2,197,607 Brown Apr. 16, 1940 2,200,064 James May 7, 1940 2,410,974 Huetten Nov. 12, 1946 2,445,390 Ellis July 20, 1948 2,480,396 Compton Aug. 30, 1949 FOREIGN PATENTS Number Country Date 1,947 Netherlands Dec. 16, 1912 OTHER REFERENCES Magnets, Underhill, pages 68 and 85, published by McGraw-Hill, New York, 1924. 

